Switch for projection machines



July 12, 1932. DlNA 1,866,550

SWITCH FOR PROJECTION MACHINES Original Filed May 31; 1928 10 l f5 Z5 5 9 I 17 20 [6 19 4 16 =5 H Z Patented 1a, 12, 1932 Aucos'ro DIN or JERSEY crrY, NEW JERSEY, moron conronA'rromor NEW 103x, 1:. 1.,

Assmnon 'ro mrmmA'rroNAr. rno- A conronA'rroN or DELAWARE swrrcn roa rnomc'rrou uAcrmms Original application fled Kay 31 1828,

This invention relates to electrical switches for projection machines, and more particularly to a new and improved mechanism for operating a switch by foot pressure.

This'application is a division of my coending application, Serial No. 281,87 2, filed ay 31, 1928, for electrical switching apparatus for picture projection machines.

An object of the invention is to provide a foot control for operating an electric switch whereby injury to the switch due to excessive pressure is avoide Another object is to provide a foot control mechanism of simplified construction which may be readily applied to a standard type of electric switch.

The invention also consists in certain new and original features of construction and combinations of parts hereinafter set forth and claimed.

Although the novel features which are believed to be chara teristic of this invention will be particularly pointed out in the claims appended hereto, the invention itself, as to itsobjects and advantages, the mode of its operation and the manner of its organization may be better understood by referring to the following description taken in connection with the accompanying drawing forming apart-thereof, in which Fig. 1 is 'a vertical section of the foot switch gig. 2 is a section on the line 2-2 of Fig. 1; an

Fig. 3 is a transverse section showing the arrangement of the casing with respect to the switch member.

Like reference characters denote like parts in the several figures of the drawing.

In the following description an in the claims parts will be identified by specific names for convenience, but they are intended to be as generic in their application to similar parts as the art will permit.

Referring to the drawing more'in detail, the inventionis shown as applied to a foot switch "control comprising a casing 2, suitably recessed to receive a switch member 3 of any well known construction. The switch member is provided with a push button 4 which is adapted on successive taining members passed over said Serial No. 281,872. Divided and this application flied Kay 20, 1829. Serial No. 804,371.

strokes to alternately open and close the circuit therethrough. The particular form of switch member, however, forms no part of the present invention and will not be described in detail. A

Cover 5, which may be secured to casing 2 by screws 6, is provided with a plurality of vertical bores for receiving push rod 7 and plungers 8. The lower portion of push rod 7 is provided with an outwardly extending flange 9 which is adapted to contact with a shoulder 10 on cover 5 to prevent the rod from I being entirely withdrawn. Cap 11 is secured to th e upper portion suitable means such as pin 12 extending through an extension of said cap and through said ush rod. The up r surface of cap 11 may e formed of any esired contour butis preferably of spherical shape as shown in Fig. 1 and formed with a radius extending through push rod 7 above shoulder 9. The force applied to the cap is thus to push rod 7 at a point where it is supported within cover 5 and the friction of said rod in said cover is reduced to a minimum.

Plungers 8 are forced against the lower surface of cap 11 by tained in the above mentioned recesses in cover 5 by suitable means, such as washer 16. Said washer may be secured to the under-surface'of cover 5 by screws 17. Cover 5 and casing 2 are formed of sufliciently strong material to prevent damage thereto by reason of the foot pressure which is exerted on cap 11. The lower portion of cap 11 contacts with the upper end of cover 5 for limiting the movement of push rod 7 whereby injury to the switch 3, which may be of comparatively delicate construction, is prevented.

Switch 3 may be secured in casing 2 by re- 18 which are secured to said 19 and a strap 20 which is switch and secured to-said switch and to members 18 by screws 21. Switch 3 is seated in a suitable recess in casing 2 and is held by the above described means in alignment with push rod 7. Casing 2 1s provided casing by screws with a pair of openings 25 through of push rod 7 by any transmitted sure of the foot which may be applied fromany convenient direction on any portion of the cap.

The switch has been shown by way of illustration as having two plungers 8 located on opposite sides of push rod 7. It is obvious,

however, that the number of plungers may be varied as desired in accordance with the requirements of a particular case.

Springs 15 should be so related to the push rod 7 and cap 11 that they automatically force these elements into raised position when the foot pressure is released, thereby allowing push button 4 to assume its normal position in readiness for another operation. By spac ing plungers 8 symmetrically about push'rod 7 the push rodis maintained in central position and the sliding friction thereof reduced.

The switch is particularly applicable to motion picture projection machines and may be located in a convenient position for foot operation. The form of the casing and cap is such that the switch may be readily located and operated by the 'foot of the operator in starting and stopping the machine.

While certain novel features of the invention have been shown and described and are pointed out in the annexed claims, it will be understood that various omissions, substitutions and changes in the forms and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention. What is claimed is: 1. A foot switch control comprising a casing adapted to receive a switch member of the intermittent push type, a cover for said casing having a plurality of bores therein, a push rod in one of said bores and engaging said switch member, an outwardly extending flange on said push rod and a cooperating shoulder on said cover adapted to be engaged thereby for preventing withdrawal of saidpush rod, a cap secured to said push rod,

and spring ressed plungers mounted in others of said ores cooperating with said cap to normally hold'said push rod in' a raised position.

2. A foot switch control comprising a casing adapted to receive a switch member of the intermittent push a cover for said casing having a plurality of bores therein, a push rod in one of said bores and engagin said switch member, a cap secured to sai push rod, and spring pressed plungers mounted in others of said bores cooperating with said cap to normally hold said push rod in a the intermittent push type, a cover for said casing having a plurality of bores therein, a push rod in one of said ores and engaging said switch member, means for preventing withdrawal of said push rod, 9. cap secured to said push rod, and means mounted in others of said bores cooperating with said cap to normally hold said push rod in a raised position.

5. A control for an intermittent push switch having a push button associated therewith comprising, a casing adapted to surround said switch, a cover supported by said casing and recessed to receive said push button, a push rod slidably held in said cover and adapted to contact with said push button, means for normally holding said push rod in raised position, and means associated with said cover for preventing depression of said push rod beyond a predetermined point.

6. A control for an intermittent push switch having a push button associated therewith comprising, a casing adapted to sur- 1 round said switch, a cover supported by said casing and recessed to receive said push button, a push rod slidably held in said cover, a cap secured to the top of said push rod, plungers cooperating with the bottom of said cap and springs secured in said cover for normally causing said plungers to exert an upward pressure on said cap.

7. A control for an intermittent push AUGUS'YI'O mm. 

